1. Field of the Invention
The present invention relates to a fabrication method and a test method for a light emitting display, more specifically to a fabrication method for a light emitting display that fabricates a pixel portion simply and conveniently using the results of testing the pixel portion in the fabrication method.
2. Description of the Related Technology
A light emitting display may be an organic light emitting display using an organic light emitting diode or may be an inorganic light emitting display using an inorganic light emitting diode. The organic light emitting diode is named as an OLED, and includes an organic light emitting layer located between an anode electrode and a cathode electrode. Within the light emitting layer electrons and holes recombine and release light of a desired color. The inorganic light emitting diode is an LED, and includes an inorganic light emitting layer. As one example, a light emitting layer is made up of a PN-junction semi-conductor, as opposed to an inorganic light emitting diode.
FIG. 1 illustrates a structure of a light emitting display according to the conventional art. Referring to FIG. 1, the light emitting display comprises a pixel portion 10, a data driver 20, a scan driver 30 and a power supply unit.
The pixel portion 10 comprises a plurality of pixels 11, a plurality of scanning lines S, S2 . . . Sn, a plurality of data lines D1, D2 . . . Dm, a plurality of first power source lines ELVdd, and a plurality of second power source lines ELVss. The pixel 11 comprises a pixel circuit and a light emitting diode, wherein the pixel circuit is connected with a scanning line S, S2 . . . Sn, a data line D1, D2 . . . Dm and a first power source line ELVdd, receives a data signal and a first supply voltage, generates a current corresponding to the data signal and then transmits the data signal to a light emitting diode. The light emitting diode has a first electrode and a second electrode. When a current flows into the second electrode from the first electrode, the diode emits light in accordance with a brighness corresponding to the amount of current. The first electrode of the light emitting diode is connected with the pixel circuit and the second electrode of the light emitting diode is connected with the second power source line ELVss. Herein, the second power source line is expressed as a plurality of wires, but is represented equivalently.
A data driver 20 is connected with a plurality of data lines D1, D2 . . . Dm, and transmits a data signal to the pixel portion 10.
The scan driver 30 is connected with a plurality of scanning lines S1, S2 . . . Sn, and transmits a scanning signal to the pixel portion 10.
The power supply unit transmits the first supply voltage through a first wire L1, and transmits a second supply voltage through a second wire L2. The first wire L1 is connected with the first power source line ELVdd and transmits the first supply voltage each pixel 11 of the pixel portion 10 through the first power source line ELVdd, and the second L2 is connected with the second power source line ELVss and transmits the second supply voltage to each pixel 11 of the pixel portion 10 through the second power source line ELVss. Accordingly, the first supply voltage and the second supply voltage are respectively transmitted to each pixel 11 of the pixel portion 10 and thus the pixel portion 10 is driven.
The light emitting display in accordance with the conventional art comprises a plurality of pixels, which are connected with a plurality of wires on a substrate. TFT's are generally formed before forming the light emitting diodes of each pixel. Before forming the light emitting diodes, an electric state of the substrate is identified by transmitting an electrical signal through a wire and then sensing a corresponding output signal. If the electric state seems to be in order after the identifying process, the light emitting display is completed by forming the light emitting diodes.
However, a light emitting display in accordance with the conventional art cannot test individual pixels without forming the light emitting diodes. Particularly, there has been a problem that in order to enhance the picture quality of a light emitting display, a number of transistors are formed in each pixel, and a transmission path of a signal in accordance with a connection of each transistor is complicated and thus a test gets more difficult.